Nine-volt battery

The nine-volt battery, or 9-volt battery, is an electric battery that supplies a nominal voltage of 9 volts. Actual voltage measures 7.2 to 9.6 volts, depending on battery chemistry. Batteries of various sizes and capacities are manufactured; a very common size is known as PP3, introduced for early transistor radios. The PP3 has a rectangular prism shape with rounded edges and two polarized snap connectors on the top. This type is commonly used for many applications including household uses such as smoke and gas detectors, clocks, and toys.[1]

Vintage PP3-size 9-volt batteries
Size comparison of batteries: D, C, AA, AAA, AAAA, PP3 (9-volt)

The nine-volt PP3-size battery is commonly available in primary zinc-carbon and alkaline chemistry, in primary lithium iron disulfide and lithium manganese dioxide (sometimes designated CRV9[2]), and in rechargeable form in nickel-cadmium (Ni–Cd), nickel-metal hydride (Ni–MH) and lithium-ion. Mercury batteries of this format, once common, have been banned in many countries due to their toxicity.[3] Designations for this format include NEDA 1604 and IEC 6F22 (for zinc-carbon) or MN1604 6LR61 (for alkaline). The size, regardless of chemistry, is commonly designated PP3—a designation originally reserved solely for carbon-zinc, or in some countries, E or E-block.[4] A range of PP batteries was produced in the past, with voltages of 4.5, 6, and 9 volts and different capacities; the larger 9-volt PP6, PP7, and PP9 are still available. A few other 9-volt battery sizes are available: A10 and A29.[2]

Most PP3-size alkaline batteries are constructed of six individual 1.5 V LR61 cells enclosed in a wrapper.[5] These cells are slightly smaller than LR8D425 AAAA cells and can be used in their place for some devices, even though they are 3.5 mm shorter. Carbon-zinc types are made with six flat cells in a stack, enclosed in a moisture-resistant wrapper to prevent drying. Primary lithium types are made with three cells in series.[6]

9-volt batteries accounted for 4% of alkaline primary battery sales in the United States in 2007, and 2% of primary battery sales and 2% of secondary (rechargeable) battery sales in Switzerland in 2008.[7][8]


PP (Power Pack) battery family from left to right: PP1, PP3, PP4, PP6, PP7, PP8, PP9, PP10, PP11

Historically, the now popular PP3 battery size was a member of the PP (Power Pack) battery family that was originally manufactured by Ever Ready in the United Kingdom and Eveready in the United States. The company says that it introduced the PP3 battery in 1956,[9] having been added as an ANSI standard in 1959, currently known as ANSI-1604A.[10]

Power Pack (PP) battery family
Name Voltage Capacity Depth Width Height
PP1 6 volt 4. Ah 55.6 mm 65.1 mm 55.6 mm
PP3 9 volt 0.5 Ah 17.5 mm 26.5 mm 48.5 mm
PP4 9 volt 0.9 Ah Dia. 25.8 mm, length: 49.8 mm; 41.5 mm ex. contacts
PP6 9 volt 1. Ah 34.1 mm 35.7 mm 69.9 mm
PP7 9 volt 2.5 Ah 46 mm 46 mm 63 mm
PP8 6 volt 15. Ah 55 mm 61 mm 200 mm
PP9 9 volt 5. Ah 51.5 mm 65 mm 80 mm
PP10 9 volt 15. Ah 66 mm 65 mm 267 mm
PP11 4.5 volt × 2 5. Ah 51.5 mm 65 mm 91 mm

The PP11 consists of two isolated 4.5-volt batteries with four terminals.

Only the PP3, PP6, PP7 and PP9 sizes are still manufactured, with the PP3 being extremely common. Modern batteries have higher capacity and lower internal resistance than early versions.

Before the mid-1950s, in the days of vacuum tube (valve) radios used batteries designed specifically for vacuum tubes, there was a nine-volt grid bias battery or (US) "C" battery, which had taps for various voltages from 1.5 to 9 volts.

Early transistorized radios and other equipment needed a suitable voltage miniature battery. Early transistor radios required a 22+12 volt battery. Although the transistors would theoretically operate from lower voltages, the point-contact transistors used in 1954 had to be operated very close to their VCB0 limit in order to get the required frequency response. However, a suitable miniature battery was already marketed for (vacuum tube) hearing aids.

The PP3 (physically identical to 6LR61 or 1604A) appeared when portable transistor radios became common, and is still called a "transistor" battery by some manufacturers.

PP3 connectorsEdit

Nine-volt battery snap

The PP3 battery has both terminals in a snap connector on one end. The smaller circular (male) terminal is positive, and the larger hexagonal or octagonal (female) terminal is the negative contact. The connectors on the battery are the same as on the load device; the smaller one connects to the larger one and vice versa.[5] The same snap-style connector is used on other battery types in the Power Pack (PP) series. Battery polarization is normally obvious, since mechanical connection is usually only possible in one configuration.

A problem with this type of connector is that two loose batteries with terminals exposed can touch and short circuit, discharging them, and generating heat and possibly a fire.[1] Keeping nine-volt batteries in their packaging until use helps to avoid accidental discharge.[11]

Technical specificationsEdit

Three different kinds of 9-volt primary battery internals: rectangular cell zinc-carbon (6F22), rectangular cell alkaline (6LP3146), and cylindrical cell alkaline (6LR61)
Rechargeable (NiMH) 9-volt battery internals (stacked, 6HF~8/~22/~17)[a]

Very often, a "9-volt" battery refers to the transistor radio size called PP3 or IEC 6F22 or NEDA 1604, although there are less common nine-volt batteries of different sizes.

Batteries of all types are manufactured in consumer and industrial grades. Costlier industrial-grade batteries may use chemistries that provide higher power-to-size ratio, have lower self-discharge and hence longer life when not in use, more resistance to leakage and, for example, ability to handle the high temperature and humidity associated with medical autoclave sterilization.[12]

Type[b] IEC
Typical capacity
Typical capacity (Wh) Nominal
Alkaline, six-cylinder 6LR61 1604A 550 4.95 9
Alkaline, six-stack 6LP3146[15] 1604A 550 4.95 9
Zinc–carbon 6F22 1604D 400 3.6 9
Lithium (varies) 1604LC[d] 1200 10.8 9
Rechargeable Ni–Cd 6KR61 11604 120 0.864, 1.008 7.2, 8.4
Ni–MH 6HR61 7.2H5 175–300 1.26-2.16, 1.47-2.52, 1.68-2.88, 7.2, 8.4, 9.6
Lithium polymer (varies) 520 3.848 7.4
Lithium-ion (varies) 620 4.588 7.4
Lithium iron phosphate 200–320 1.92-3.072 9.6

Testing and chargingEdit

Most battery voltage testers and chargers that can also test nine-volt need another snap clip to hold the battery, while cylindrical batteries often share a holder that may be adjustable in size. Because of the proximity of the positive and negative terminals at the top of the battery and relatively low current of most common batteries, one informal method of testing voltage is to place the two terminals across a tongue. A strong tingle would indicate a battery with a strong charge, the absence, a discharged battery. While there have been stories circulating of unfortunate outcomes, the process is rarely dangerous under normal circumstances, though it may be unpleasant.[16]


Lithium 9-volt batteries are disposable high-energy-density batteries. In the PP3 size they are typically rated at 0.8–1.2 Ah (e.g. >1.2 Ah @ 900 ohms to 5.4 V @ 23 °C for one type),[17] about twice the capacity of alkaline batteries. Some manufacturers claim the energy density can be five times that of alkaline.[17] Common applications for lithium nine-volt batteries are smoke and carbon monoxide detectors.[6]

See alsoEdit


  1. ^ Presumed cell size.
  2. ^ Some types are not found in a battery nomenclature, hence N/A.
  3. ^ The granularity of IEC nomenclature means that each cell may have more than one match. This is partially due to the chemistry types being open to interpretation (especially for lithium cells) and partially due to the possibility of different geometric constructions (e.g. stacked versus cylinder). For example, the NiMH code listed in the table (6HR61) assumes a cylindrical geometry and would not apply to the pictured NiMH cell.
  4. ^ There is a similar issue in "lithium" being vague here. The example gives LC, the three-volt Li–MnO2 system. Alternatively six 1.6-volt Li–FeS2 cells may be used, giving 1604LF (or 6FR61 in IEC).


  1. ^ a b "9-Volt Battery Safety". National Fire Protection Association. 2016. Archived (PDF) from the original on 2016-07-27. Retrieved 2022-05-01.
  2. ^ a b "Non-Rechargeable Batteries (filtered for 9V)". CPC Farnell. Retrieved 2022-04-22. 9-volt batteries supplied by a typical distributor: PP3 (or CRV9), PP6, PP7, and PP9 are the PP sizes; A10 and A29 the only other 9v types.
  3. ^ Hunter, Rod; Muylle, Koen J., eds. (1999). European Community Deskbook. An ELI deskbook - ELR - The Environmental Law Reporter. Environmental Law Institute. p. 75. ISBN 0-911937-82-X.
  4. ^ "AP300 NiMH 9 Volt 300mAh". AccuPower. Archived from the original on 2018-02-06. Retrieved 6 February 2018.
  5. ^ a b IEC 60086-2-2011 §
  6. ^ a b Lee, Arthur (2002-06-28). "Preliminary Test Results on Lithium Batteries Used in Residential Smoke Alarms" (PDF). U.S. Consumer Product Safety Commission. Archived from the original (PDF) on 2017-02-23. Retrieved 2022-07-24.
  7. ^ "Life Cycle Impacts of Alkaline Batteries with a Focus on End-of-Life" (PDF). EPBA-EU. Archived from the original (PDF) on 2016-03-03.
  8. ^ "INOBAT 2008 Statistics" (PDF). Archived from the original (PDF) on 2012-03-25.
  9. ^ "Battery History". Energizer. Retrieved 2018-02-16.
  10. ^ "Product Datasheet: Energizer 522" (PDF). Energizer. 2019-10-25. Retrieved 2022-03-26.
  11. ^ "9 Volt Batteries a Fire Hazard". Division of Fire Safety – NH Department of Safety. 2017-01-29. Archived from the original on 2017-01-29.
  12. ^ Adams, Louis (November 2015). "Powering Tomorrow's Medicine: Critical Decisions for Batteries in Medical Applications". Medical Design Briefs.
  13. ^ IEC 60086-2011 pt2-§
  14. ^ ANSI C18.1M Part 1 and C18.3M Part 1
  15. ^ "MN1604" (PDF). Bethel, Connecticut: Procter & Gamble. Archived from the original (PDF) on 2018-05-27. Retrieved 2022-02-12.
  16. ^ "The Science of Licking a 9V Battery".
  17. ^ a b "Farnell: Datasheet for Ultralife U9VL-J-P 9V lithium manganese dioxide PP3-size battery" (PDF).

External linksEdit